1. Field of the Invention
The present invention relates to crown rolls, and more particularly to crown rolls which provide adjustment of the roll shell, heating of the shell with respect to the product and insulation of the roll bearings from the heat of shell heating.
The present invention also relates to improvements in controlled deflection rolls and particularly to a roll which is to operate at a predetermined elevated temperature with means for controlling that temperature.
More particularly, the improvement relates to a controlled deflection roll of the type which has a tubular rotatable roll shell supported on a through shaft. The roll shell is supported and prevented from deflecting by transferring a working load through the roll shell to a pressure means between the shaft and the roll shell. Preferably, the pressure means is in the form of a piston extending axially along the shaft with supporting oil beneath the piston. The piston has an outer face with pockets which provides for lubrication between the roll shell and piston. A support oil is utilized to support the piston and control the roll shell deflection and to provide the lubrication between the piston and roll shell. In the present arrangement, a heat transfer oil is arranged to operate at a predetermined elevated temperature so as to maintain the roll shell at a predetermined temperature.
2. Description of the Prior Art
Typical of well-received crown rolls is the crown roll, commonly known as the swimming roll, disclosed by Kusters et al. in their U.S. Pat. No. 3,131,625; however, there is no provision for a thermal buffer from the roll shell heating space to the bearing. The same is true with respect to Christ et al U.S. Pat. No. 4,282,638 and 4,282,629. The known art, however, does not go to the problem of reducing bearing heating.
In devices of this type heretofore used, difficulties were encountered in heat loss from the oil. The heat loss which occurred in an axial direction resulted in excessive heat transfer and damage to the bearings. Also, in some instances the same oil was used for the bearings which created difficulties because of the high temperatures which were encountered.